Introduction

Cancer is a relatively neglected disease, as declared by Soyannwo [1], that is still an overriding cause of pain and suffering, especially in developing countries [1–4]. According to the World Health Organization (WHO), 8.2 million people die from more than 100 types of cancer each year [3]. More than half of all new cancer cases occur in developing countries [3, 4], and the incidence of new cancer cases is expected to increase by a further 70% in the next two decades [3–6].

Of all the symptoms experienced by cancer patients, pain is the most common complaint and, at times, patients can find it intense and unbearable [7, 8]. Cancer-related pain on average affects as many as 50–75% of patients worldwide [9–11]. According to a systematic review by van den Beuken-van Everdingen et al. evaluating 54 related articles, 59% of patients undergoing cancer treatment and 64–75% of patients with advanced disease were affected by pain [9]. As such, cancer-related pain is a greater problem during the advanced stages of the disease, which can become the predominant problem for both the patients and their families [10–12].

On the basis of van den Beuken-van Everdingen et al.’s systematic review, more than one-third of cancer patients graded their pain as moderate to severe with a visual analogue scale (VAS) greater than 4 [9]. Likewise, of 258 hospitalized cancer patients interviewed about their pain in a study by Ripamonti et al., more than half experienced it in the 24 h prior to their admission with 27.1% of them regarding it as high degree [11]. Cancer pain of this intensity is highly prevalent in resource-poor countries and this adversely impacts different aspects of sufferers’ lives including psychological, social, cultural, and spiritual facets [13]. Female gender, young age, and prolonged hospitalizations have been associated with increased pain severity [12].

Since the early 1950s, when John Bonica highlighted the importance of pain relief, pain has been recognized, not just as a symptom or sensation but as a disease in itself [14]. With the development of pain medicine as a subspecialty of medical practice in 1989, this domain gained further popularity. Today, failure in the adequate treatment of pain is not only unethical but also illegal [14–16].

Based on WHO guidelines, and depending on the extremity of pain, step by step management begins with oral non-opioid analgesics and progresses through to parenteral opioids, anticonvulsant agents, or local anesthetics [17]. There are also diverse interventional techniques such as spinal analgesia, nerve block, or destructive modalities (like radiofrequency ablation reserved for a minority of patients) [18].

Despite the fact that cost-effective methods for pain care are available, acute and chronic pain is still undertreated in developing countries [13, 19]. There seems to be a large and widening gap between the increasingly sophisticated knowledge of pain and the application of this knowledge to effectively treat patients [16, 18]. Besides the lack of pain management training at both undergraduate and postgraduate levels [20], there are several other barriers to desirable pain alleviation in resource-limited settings, including timely access to healthcare [21] or economic impediments [22]. However, given the overwhelming need to treat cancer-related pain, local advocates have a pivotal role in developing and implementing innovative measures, despite the limited resources available [10, 16, 23, 24]. To overcome the challenges in the management of cancer-related pain in developing countries, it is vital that pain control is embedded in different models of healthcare delivery. The quality of care given must also be strengthened. Both of these needs can be met through the establishment of regional and educationally oriented research centers [10, 16]. This paper offers a concise summary of the studies that have been performed in the field of cancer pain and its management in Iran as one of the developing countries.

Materials and Methods

To assess the level of pain and cancer pain knowledge in Iran, a brief search of the literature including papers published in PubMed before March 2016 (using keywords “pain”, “cancer pain” with/without “Iran”) was carried out. This article is based on previously conducted studies and does not involve any new studies of human or animal subjects performed by any of the authors.

Results

The findings illustrated in Figs. 1 and 2 indicate a significant annual progression in studies related to pain and cancer pain. There have been an increasing number of publications on pain since 1842 and a growing number of publications on cancer pain since 1929. In very recent years, there has been remarkable growth our understanding of cancer pain, particularly since 2010. In fact, more than one-third of studies on pain and cancer-related pain were published after 2010.

Fig. 1
figure 1

Progression in pain research, especially in the recent decade

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Fig. 2
figure 2

Progression of pain and cancer pain-related knowledge annually. About one-third of pain knowledge was developed since 2010

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Discussion

Iran’s contribution to both pain and cancer-related pain research has increased in the last decade. Of the total number of papers originating from Iran, at least according to the PubMed database, 91.8% are related to the last 10 years and more than half (61.7%) are related to the last 5 years. On top of that, the ratio of cancer pain-related papers to the total papers about pain has been around 8% which is slightly less than the corresponding ratio globally (13%). This significant upward trend once more highlights the importance of this topic particularly in developing countries. As a limitation of our study, we knew that there are many databases (Google Scholar, Scopus, EMBASE, etc.) which should be included in a more comprehensive literature review; however, we selected PubMed as one of the most referred to databanks globally. We suggest that new projects be undertaken to write an original or review article in the field of pain research development.

The growing tendency among Iranian anesthesiologists to study and practice in pain medicine spurred the establishment of the Iranian Society of Regional Anesthesia and Pain Medicine (ISRAPM) in November 2006. This society aimed to improve and support scientific and educational activities within this field, and in the last decade, there has been an improvement in pain education and clinical practice in Iran. This has been achieved by providing training through pain fellowships and publishing pain guidelines in Anesthesiology and Pain Medicine.

Pain relief is a human right [17, 18] and as such Iranian pain physicians are now concentrating on performing more native research projects, publishing research articles, and managing pain departments and pain research centers. For example, one of the most distinguished and successful pain departments is at MAHAK hospital, which focuses on pediatric cancer pain. Many different types of cancer have been reported in children admitted to MAHAK’S Pediatric Cancer Treatment and Research Center (MPCTRC) including acute lymphocytic leukemia (ALL), acute myelocytic leukemia (AML) [25], central nervous system tumors such as primitive neuroectodermal tumor (PNET) [26], and soft and hard tissue tumors [27].

MPCTRC is equipped with a wide range of facilities including an operating room, ultrasound, and laser and ozone therapy units. Acute and chronic pain control has become achievable with the help of transcutaneous electrical nerve stimulation (TENS), peripheral and central neural blockade, or epiduroscopy (diagnosis and treatment of epidural space adhesions resulting from spine surgery or tumor invasion). Other interventional pain management techniques accessible at this center include the use of radiofrequency and microwave for modulation, ablation, and coagulation of pain pathways, implantable analgesic pumps in the epidural or intrathecal space, along with botulinum toxin injection therapy (for headaches, muscle pains, and spasms), photodynamic therapy, aromatherapy, and music therapy [28]. There are many disease-based projects undertaken at this center [25–28]. There are also a number of ongoing projects investigating the follow-up of cancer patients since 2014, which are due to be completed by 2020. The number of cancer patients referred to MAHAK since 2008 is shown in Table 1.

Table 1 Number of patients with different types of diseases referred to MAHAK since 2008
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Overall, the establishment of MPCTRC has been successful in improving the quality of life in children affected by cancer [28]. As stated by recent studies, each cancer center should be supplied with a specific pain department in order to reduce cancer patients’ distress. This is of significant importance among physicians [28]. MAHAK supports the treatment of cancer-stricken children by providing them with specialized services that still allow them to enjoy their childhood whilst undergoing treatment. This allow the patients to have the highest possible quality of life in accordance with international standards [23, 28].

Conclusion

There is a need to be more inventive with the management of cancer-related issues in developing countries to maximize the use of available tools. With regard to the paucity of knowledge and limited resources in this area, the critical role of the non-governmental organizations, such as MAHAK, should not be overlooked.